Obviously a very open question.... I think it is useful to understand the broader user-base of thermostats and weather-related devices and automations when embarking on a setup involving a HE hub...
Obviously everyone should be installing an EcoWitt and Mitsubishi setup like me .... 
But for those who don't subscribe to this setup.... I would encourage further investigation on the Community...
I’ve purchased a Tempest Weatherflow a few years back now.
I use the illuminance value to decide if some lights should turn on automatically or not.
I use the temperature value to decide what my mini-split temperature should be set to, and if it should possibly be turned off depending on the illuminance value (good sunny day warms up the house).
I use the rain/no rain result along with my window sensors and wind direction to alert me to close certain windows as needed.
There may be more, but those are the main ones. 
Honeywell T6 and a Tempest weather flow. My big automation for the weatherflow is if it starts raining, Hubitat will check if any windows are open. If one is, Hubitat will announce which one(s) on all the speakers in the house and repeat every 5 mins till closed. (we have a virtual switch to silence all announcements)
For thermostat it's lower it at night when we shutdown the house and at 5 am start bringing it up again (or cooling depending on the season)
Ecowitt here. We don't really open and close windows, so the weather station does not particularly affect the thermostat operations. However, I did set up automation for whether we are away or home with home having settings for day or night. The lighting is motion controlled. If they were not so expensive, I would not mind getting automated drapes and/or shades. The price would really need to come down on those, given the number of windows I would want to do.
My approach has typically been to purchase one piece at a time… And now everything that can be automated (where a product exists and I am aware of it, and it makes sense) has been automated.
Ecobee and Ambient weather station. Ecobee runs HVAC very well. The only minor integrations, are we use Hubitat presence to set home and away HVAC modes, and turn on the system fan when bathroom humidity is x above the bedroom where the Ecobee lives. Also automatically turn on system fan when "cleaning" is enabled for a few hours weekly. Ambient weather is used for a few rules with outdoor temp and lux level.
Interesting. Is this to address indoor air quality during cleaning/dusting?
I have an Ecowitt weather station. For accessories with it, I have the floating pool thermometer, three soil moisture sensors, several temp humidity sensors, and a temperature sensor with a probe.
I use my Ecowitt in automations for watering the gardens using the moisture sensors and some smart valves. I wrote an irrigation app to control it. I use the probe temp sensor inside a solar pool heater, with automations to turn it on when it is at temp, and the pool is not over temperature (that never happens!). I have a temp humidity sensor in my attic to run my attic fan, based on both temp and humidity, compared to the outdoor Ecowitt temp and humidity. I vent when the attic is over temp, or when humidity is higher in the attic than outside, even in the winter.
I have three Honeywell T6 Zwave thermostats, but I only use them as interface panels to three virtual thermostats. My heat is actually run from the virtual thermostats that sync to the physical T6s, and I use temp sensors and a Zigbee relay board to run my zone valves. I didn't like how the T6s controlled my heat, so I wrote my own thermostat driver that anticipates when the heat needs to come on, and then uses timed cycles to keep a very consistent temperature.
We have someone that comes in and cleans every two weeks. Her door unlock code turns most of the lights in the house on, lowers the thermostat and runs the HVAC fan to aid in the capture of any dust that may get stirred up. When she tells Alexa to "Turn off cleaning." a virtual switch enables Ecobee "resume program," restores Ecobee to its current comfort settings and turns off most of the lights.
Ecobee Premium Thermostat.
Ecowitt WS90 Weather Station plus few Gateways (because of multiple CO2 Sensors) plus many other Ecowitt Sensors.
There are many weather-based automations including automatic open/close balcony doors (yes, equipped with actuators).
Basically all my controls/automations are 100% automatic (all local control) but with ability for manual interactions (request from my wife). Voice Control is not used at all but there are few voice announcements.
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